CN101304876A

CN101304876A - Oriented multi-layer shrink labels

Info

Publication number: CN101304876A
Application number: CNA2006800422914A
Authority: CN
Inventors: R·M·帕特尔; D·H·尼曼; 覃伯荣; M·阿蒙; E·罗森包姆; 褚嘉希
Original assignee: Dow Global Technologies LLC
Current assignee: Dow Global Technologies LLC
Priority date: 2005-11-15
Filing date: 2006-11-02
Publication date: 2008-11-12
Also published as: AR057578A1; RU2008123819A; ZA200804210B; JP5427411B2; EP1951524B2; KR20080074177A; CA2628427A1; US20090220757A1; DE602006016160D1; ATE477113T1; BRPI0620471A2; CN103692746B; EP1951524B1; CN103692746A; AU2006315832A1; US8541077B2; EP1951524A1; RU2415014C2; JP2009515733A; WO2007058783A1

Abstract

The present invention relates to a multi-layer oriented shrink film comprising at least one skin layer comprising a polystyrene material and at least one core layer comprising a polyolefin layer. The films are preferably primarily oriented in either the machine or the cross direction. These films are ideally suited for use as a shrink label which can be applied either as a CD shrink sleeve or applied using a continuous roll process. The films ideally have an overall density of less than 1.0 g/cm<3>, to facilitate recycling efforts.

Description

Oriented multi-layer shrink labels

Technical field

The present invention relates to the oriented shrink plural layers, it comprises that at least one comprises amorphous glassy polymer material, and for example the top layer of polystyrene material comprises the central core of polyolefin layer with at least one.Described film is mainly in vertical or horizontal preferred orientation.These films are ideally suited as shrink label, and this label can be used as CD and shrinks the cover use or be used for the continuous rolling process.Described film has ideally less than 1.0g/cm ³Gross density, thereby convenient use moisture floatation separating technology to carry out circular treatment.

Background technology and summary of the invention

Shrink label is divided into two classes usually: with rolling up with (roll-on shrink-on, ROSO) label and the sleeve label (sleeve-type label) (sleeve labels) of contracting.The ROSO label is the diaphragm around container pack.Sleeve labels is a tubular structure, is surrounded on container on the container by being enclosed within.Heating ring can make label shrink and fits with container around the shrink label of container.

In order to fit with container, every type label must shrink (promptly bigger in another direction shrinkage degree a direction ratio) at the orientation preferentially that circumferentially extends around container.The ROSO film is positioned on the container, and vertical (MD) of film circumferentially extends around container.Because preferentially machine-direction oriented (MDO), so the ROSO film mainly shrinks along vertical (MD) of film.By contrast, sleeve labels is positioned on the container usually, and horizontal (transversedirection) of label (TD) (is also referred to as laterally (cross direction) or " CD ") and circumferentially extends around container.Because preferential horizontal orientation (TDO), so sleeve labels is mainly shunk along horizontal (TD) of film.

Special demands to the ROSO label surpass sleeve labels, because the required processing of ROSO label is less and preparation cost is lower.On alignment films, print man-hour owing to adding, make the ROSO label be web-like usually at continuous coiled material.By contrast, sleeve labels although also be web-like, need printing, cutting, bondingly advances sleeve pipe before being rolled into web-like, and sleeve labels is with respect to the ROSO label, and its production process is complicated and increased production cost.In addition, owing to compare with the machine-direction oriented film that is used for the ROSO label, equipment cost is higher relatively, and the horizontal orientation film that is used for sleeve labels is often more expensive.In addition, using the ROSO label on container processes sooner than application of sleeve labels usually.

Although the ROSO label has advantage on speed of production, sleeve labels has advantage in history on the shrinkage degree around container.Sleeve labels is around 70 percentages (%) at the most usually of the contraction around the container.By contrast, history shows that common ROSO film is the highest by only about 20% around the contraction around the container.For the ROSO label, needs contraction in the vertical is greater than 25%, more preferably greater than about 50%.Common ROSO label shrink low mainly be because: (1) is for film, the main oriented polypropylene (OPP) that uses, a kind of crystalline polymer, (2) restriction allows to act on the stress on the viscose glue seam (glue seam), this viscose glue seam makes label be fixed on appropriate location (parcel) around container---acts on stress on the viscose glue seam and crosses senior general and cause that label is at the container superior displacement, perhaps under extreme case, cause that gluded joint lost efficacy, label is no longer around container pack.Therefore, for film, observed shrink tension is to be used for determining whether it is suitable as a key factor of ROSO label, usually preferred lower shrink tension.Sleeve labels does not have gluded joint or have the gluded joint that largely solidifies before being used for container, can tolerate stress greatly in contraction process.

Sleeve labels is enjoyed in history greatly and being shunk, and therefore can fit with container is peripheral better than ROSO label.But, consider the production advantage of ROSO label, need identification to be fit to the alignment films of preparation ROSO label, it can be than current ROSO label (promptly, more can compare with sleeve labels) circumferentially be contracted to bigger degree around container, but again without detriment to the inefficacy of label gluded joint.

Polystyrene (PS) is used to prepare the shrink label film sometimes, because PS still keeps higher surface energy with respect to PP during time lengthening after sided corona treatment (is necessary for the thin polymer film surface that is suitable for printing is provided).Therefore, different with the PP film, the sided corona treatment of PS film can be carried out at production period, rather than only carries out before printed label.

Polystyrene-based shrink label films often comprises high impact polystyrene (HIPS) component to improve label toughness (for example, tear resistance).But the rubber particles in common HIPS scope has average particle size greater than a micron (see, United States Patent (USP) (USP) 6897260, the 4 hurdles for example, 26-27 is capable).Big rubber particles tends to reduce the transparency of label film, disturbs and uses film to carry out back up (be printed on make it see through film on the face of label film adjacent vessel be readable), and disturb and see through label and observe container or product.Common HIPS also comprises with the total restatement of HIPS greater than 7% rubber.High concentrations of rubber can hinder the impressionability (printability) of film, reduces the transparency of film, and stability reduced in size also undesirably increases the gel content of final film.

Compare with polyvinyl chloride (PVC) film with copolyester, use the PS film to make things convenient for the recycling of bottle and label, because lower density makes that label is easier and separates with higher density (for example, polyester) bottle.If it is recycling that the density of shrinkable film will more help less than 1.0g/cc, because this will allow floatation separating technology.

In addition, more low-density film helps the film yield that provides higher, perhaps the film of large tracts of land/lb more.The label stock of higher density, for example copolyester or PVC film do not have similar advantage.

Need a kind of oriented multilayer film that is applicable to ROSO or shrink sleeve label.

The U.S. Provisional Application 60/703385 that on July 28th, 2005 submitted to, be incorporated herein its full content as a reference, instructed a kind of biaxial orientation polystyrene base film of the ROSO of being suitable for use as label, HIPS rubber particles size that it comprises and rubber concentrations are lower than common HIPS's.A kind of shrinkable film need be provided, and it shows the littler shrink tension of film than instruction in 60/703385.The gross density that also needs shrink film is less than about 1g/cm ³, label is separated with bottle with the convenient flotation technology that in cyclic process, adopts.

Therefore, on the one hand, the present invention is a kind of oriented multi-layer shrink film, and it comprises that at least one comprises amorphous glass polymers, and for example the top layer of polystyrene material comprises the central core of polyolefin layer with at least one.Described multilayer film can for example use one group of MDO roll in vertical preferred orientation; Perhaps, for example use stenter method (tenter frame process) laterally.The preferred polystyrene material of amorphous glassy polymer material, as known usually in the prior art, it can be general purpose polystyrene (GPPS) or can comprise that other styrenic material are to give durability and toughness.These other materials comprise for example high impact polystyrene material, SBC, for example K-resin (available from Chevron Phillips), SBS (styrene butadiene styrene triblock copolymer), SIS (styrene isoprene styrene), SEBS (styrene ethylene-butylene styrene triblock copolymer) and/or its combination.When the needs high impact polystyrene, film preferably comprises a kind of high impact polystyrene, it is compared with common HIPS has littler rubber particles and lower rubber concentrations, thereby makes film obtain toughness and do not hinder impressionability, transparency or the contact transparency of film.At the used polyolefin of at least one central core, look the needs that expection is used, preferably can the selected contraction of controlling the shrink tension and the film of film.

On the other hand, multilayer film of the present invention also is included in the one or more binder courses between polyolefin layer and the polystyrene skin.

On the other hand, the present invention a kind ofly comprises first or the shrink label of the described plural layers of second aspect, and wherein this film has printing at one or both sides.

Description of drawings

Fig. 1 is the figure of the MD contraction data of show sample 3-1 and 3-2 film.

Fig. 2 is the figure of the CD contraction data of show sample 3-1 and 3-2 film.

Fig. 3 is the figure of the MD contraction data of show sample 4-1 to 4-4 and 5 films.

Fig. 4 is the figure of the CD contraction data of show sample 4-1 to 4-4 and 5 films.

Detailed Description Of The Invention

Oriented multi-layer shrinkable film of the present invention comprises that at least one top layer that comprises amorphous glass polymers and at least one comprise other layers of polyolefin layer. The preferred polystyrene material of amorphous glassy polymer material. Plural layers of the present invention preferably comprise the second top layer at reverse side, the polyolefin layer that it comprises amorphous glassy polymer material and comprises central core. The preferred material in the second top layer is identical with the first top layer. Randomly, plural layers can be included in the one or more binder courses between top layer and the polyolefin layer.

A, top layer

The top layer comprises amorphous glass polymers.Amorphous glass polymers has the glass transition temperature (determining according to peak value suitable on tan (δ) curve that adopts dynamic mechanics heat analysis to survey) that exceeds room temperature and is (promptly the utilizing as the determined degree of crystallinity of wide angle X-ray diffraction less than about 10 weight %) of amorphous state basically.Amorphous glass polymers comprises polystyrene material (for example GPPS, HIPS, K RESIN, SIS, SBS, SEBS) and PETG, amorphous PET, amorphous state PLA or PVC.When using GPPS as amorphous glassy polymer material, the Mw (weight average molecular weight) that needs GPPS is greater than 100, and 000g/mol is preferred 150,000g/mol or bigger, more preferably 200,000g/mol or bigger.The Mw (weight average molecular weight) that also needs GPPS is less than about 350,000g/mol, and preferably less than about 320,000g/mol.Mw can determine according to gel permeation chromatography well known in the prior art.Needing the melt flow rate (MFR) (MFR) of GPPS is 1 or bigger, preferred 1.2 grams per 10 minutes (restrain/10 minutes) or bigger, and need 20 grams/10 minutes or littler, preferred 10 restrain/10 minutes or littler.The MFR of polystyrene determines according to ASTM method D1238 (200 ℃ of following 5 kilograms of weight).

The example of suitable GPPS comprises STYRON ^TM663 general purpose polystyrenes (STYRON is the trade mark of The Dow Chemical Company), STYRON 668 and STYRON685D.

Bigger if desired ductility and/or toughness, then one or two top layer can comprise other materials, for example HIPS, SBS, K-resin, SIS, SEBS etc.These other materials are preferably in order to keep optical clarity.The name of submitting on July 28th, 2005 is called in the U.S. Patent application 11/191817 of " IMPROVEDRUBBER MODIFIED MONOVINYLDENE AROMATIC POLYMERSAND THEMOFORMED ARTICLES (improved rubber modified monovinylidene aromatic polymers and goods thereof) " has described the useful especially HIPS of a class that is applicable to one or more top layers of the present invention, is incorporated herein its full content as a reference.

Amorphous glassy polymer skin layer can comprise other additives, for example mineral oil or other plasticizer, and known additives usually in other prior aries.These materials comprise for example inorganic filler, conductive filler, pigment, antioxidant, acid scavenger, fire retardant, ultra-violet absorber, the processing aid as zinc stearate, extrusion aid, slip additive, permeation of modified agent, antistatic additive, anti-caking additive and other thermoplastic polymers.

Consider that also described top layer can comprise other amorphous glass polymers, for example PETG (PET, G), amorphous PET (PET), amorphous state PLA (PLA).Polyvinyl chloride (PVC) and/or its combination.These materials tend to have higher density, and this gross density that will cause film is greater than 1g/cm ³, make film for recycling consideration less be subjected to preferred.

Also consider the combination that in one or two top layer, can use two or more amorphous glass polymers.

Described top layer preferably accounts for 10 weight % to 80% of plural layers weight of the present invention, and more preferably 10% to 70%, more preferably 20% to 50%, most preferably 30% to 50%.

B) polyolefin layer

Plural layers of the present invention also comprise the second layer that contains polyolefine material.Preferred polyolefine material comprises Polyethylene homo and copolymer and polypropylene homo and copolymer.These comprise low density polyethylene (LDPE), LLDPE, very low (or ultralow) density polyethylene, polyethylene plastomers and elastomer, for example evenly linear tetrafluoroethylene polymer and substantially linear ethene polymers, intermediate density polyethylene and the high density polyethylene (HDPE) of branching), homopolymer polypropylene (" hPP ") random copolymer polypropylene (" RCP ") and acrylic plastic body and elastomer, those described in the WO 03/040442 for example, be incorporated herein its full content as a reference, and combination.Most preferably polyolefin plastomers and elastomer, particularly polyethylene plastomers and elastomer and polypropylene plastics gonosome and elastomer, comprise acrylic plastic body described in the U. S. application of submitting in WO03/040442 and on August 19th, 2,005 60/709688 and elastomer (full content that is incorporated herein above-mentioned each patent as a reference---in these materials some can be from The DowChemical Company with trade name Versify ^TMBuy) and by ExxonMobil Chemicalcompany with trade name Vistamaxx ^TMAcrylic plastic body and the elastomer sold.The density of polyolefin central core is preferably less than 0.920g/cm ³, be more preferably less than 0.90g/cm ³, be more preferably less than about 0.89g/cm ³, most preferably less than about 0.88g/cm ³

Can select polyolefin component so that suitable fusing point and degree of crystallinity to be provided, thus the shrink tension of control film.Preferably, the fusing point of selected vistanex (or blend) is below 150 ℃, is more preferably less than 135 ℃, also is more preferably less than 120 ℃, most preferably less than 100 ℃.

Described polyolefin component can also advantageously comprise common known multiple additives in the prior art.These materials comprise for example inorganic filler, conductive filler, pigment, antioxidant, acid scavenger, fire retardant, ultra-violet absorber, processing aid, extrusion aid, slip additive, permeation of modified agent, antistatic additive, anti-caking additive and other thermoplastic polymers.

Described polyolefin layer preferably accounts for 20 weight % to 90% of plural layers weight of the present invention, and more preferably 30% to 90%, also more preferably 50% to 80%, and also more preferably 50% to 70%.

C) binder course

Plural layers of the present invention can also randomly comprise one or more binder courses.Binder course helps assisting in ensuring that the excellent bonds between glassy amorphous polymeric layer and inside or site polyolefin layer.Suitable polymer as binder course when using polystyrene material on the top layer comprises SEBS and SEPS block copolymer and preparation, EVA, SBS, SIS, K-resin and combination thereof.

Described binder course can also advantageously comprise common known multiple additives in the prior art.These materials comprise for example inorganic filler, conductive filler, pigment, antioxidant, acid scavenger, fire retardant, ultra-violet absorber, processing aid, extrusion aid, slip additive, permeation of modified agent, antistatic additive, anti-caking additive and other thermoplastic polymers.

Described binder course if any, preferably accounts for 5 weight % to 15 weight % of whole plural layers.

Whole film

The resin that is preferred for each layer exists in the plural layers, make film according to the determined gross density of ASTMD-792 less than 1.0g/cm ³, be more preferably less than 0.98g/cm ³

Film of the present invention is orientated, and this is meant that they have uniaxial orientation or biaxial orientation, and its preferred orientation is vertically (MD) or laterally (CD).Preferred orientation is meant vertical or horizontal orientation ratio big in other directions.Be 2x at least in the degree of orientation of MD or CD, preferred 3x at least, 4x at least most preferably, this depends on required shrinkage direction.The shrink tension of oriented shrink films of the present invention usually greater than about 50psi, is preferably greater than 100psi under 135 ℃.Although the MDO ratio of film is generally 20 or littler, the MDO ratio does not have the clear and definite upper limit.The MDO ratio greater than the risk of 20 film is, shrinks around container with high active force in the ROSO tag application so that weakens or lost efficacy around the viscose glue seam of bottle fixed labels.This also is real for the TDO ratio in shrink sleeve applications.

Use vertically long 10 centimetres, horizontal long 2.5 centimetres the MDO ratio of the machine-direction oriented ROSO label of sample determination.Sample is placed hot oil bath, keeping 30 seconds (ASTM D2732) more than the fusing point of the highest molten resin and more than the glass transition temperature on the top layer.And then measurement longitudinal size.Heat before with heat after the longitudinal size ratio corresponding to the MDO ratio.

Use laterally long 10 centimetres, vertical long 2.5 centimetres the TDO ratio of sample determination horizontal orientation shrink sleeve label.Sample is placed hot oil bath, and it is above and more than the glass transition temperature on top layer 30 seconds (ASTM D2732) to remain on the fusing point of the highest molten resin.And then measurement lateral dimension.Heat before with heat after the lateral dimension ratio corresponding to the TDO ratio.

Plural layers of the present invention can adopt the conventional preparation of following method before orientation step: cast film method, inflation film process, extrusion coating method or laminating, and preferred curtain coating membrane process.

Can select to be used for the film temperature of film production process stretching/orientation process, to help the control shrink tension.The film stretching temperature is preferably 100 ℃ to 150 ℃, more preferably 120 ℃ to 135 ℃.

When needs MD is orientated, use one group of MDO roll to realize easily.When needs CD is orientated, use the stenter method to realize easily.These and other are well-known in the prior art in order to the step that realizes orientation.

Particularly when plural layers of the present invention were used for the ROSO label, the shrink tension of this film should be more preferably less than 400psi less than about 500psi, is more preferably less than 300psi, most preferably less than about 250psi.Sleeve labels can be tolerated higher shrink tension, for example greater than 1100psi, even greater than 1400psi.Shrink tension is determined according to ASTM D-2838.

Film of the present invention need show that in normal shrink label application temperature (be 110 ℃ to 140 ℃ for ROSO for example, for sleeve pipe is 110 ℃ to 130 ℃) under, be punctured into 20% or more in preferred orientation direction when orientation (temperature 120 ℃ to 130 ℃ down), preferred 30% or more, more preferably 40% or more, also more preferably 50% or more, more preferably 60% or more, even be 70% or more in differently-oriented directivity more preferably also.Contraction below 20% often undesirably limits the degree that film and container periphery fit.Although the upper limit of shrinkage degree is unknown, it is below 100%.

Need ground, film shows that in normal shrink label application temperature (be 110 ℃ to 140 ℃ for ROSO for example, for sleeve pipe is 110 ℃ to 130 ℃) under, be punctured into 30% or still less in the direction opposite when orientation (temperature 120 ℃ to 130 ℃ down) with preferred orientation, preferred 20% or still less, more preferably 10% or still less, also more preferably 5% or still less.The contraction that should be appreciated that " less than 5% " also comprises growth, be minimized although increase.

In some of label industry are used, need transparency (particularly contacting transparency) and diaphaneity (transparency) with from the tag location non-fuzzy observe product.Also need the high grade of transparency and diaphaneity to be used for " oppositely " printed label, wherein printing is positioned between label and the container, and the consumer observes printing by label.Normally, when film of the present invention was 2.0 mils (50 m) at thickness, its transparence value was 10 or higher, preferred 15 or higher, more preferably 20 or higher, more preferably 25 or higher, also more preferably 30 or higher.D-1746 determines transparency according to the ASTM method.

Haze value also provides a kind of tolerance to film clarity, and low haze valus is corresponding to the high grade of transparency.The haze value of film of the present invention can be any possible values.But an advantage of the present invention is can obtain to have the oriented film of the high grade of transparency and low haze valus.When film of the present invention was 2.0 mils (50 m) at thickness, its haze value was generally 20 or lower, preferably less than 15, and more preferably 10 or lower, still more preferably 8 or lower, also more preferably 6 or lower, most preferably 4 or lower.D-1003 determines haze value according to the ASTM method.

In order suitably to distribute the ROSO label under high linear velocity, the rigidity of plural layers of the present invention is important in other reasons.Rigidity at the plural layers of preferred orientation direction orientation should be at least about 5Gurley, can be as high as 150Gurley usually.More frequently, the rigidity of the plural layers of orientation is measured as 20 to 70Gurley according to TAPPI Gurley implosion test T543pm.

Though described film can have any required thickness, the gross thickness of film of the present invention is generally 1 mil (25 μ m) or higher, and preferred 1.5 mils (38 μ m) or higher are generally 4 mils (100 μ m) or lower, preferred 3 mils (76 μ m) or lower.Film thickness is during less than 1 mil (25 μ m), and the cutting film is quite difficult often in processing and processing procedure.Thickness greater than 4 mils (100 μ m) can reach technically, but normally undesirable economically.Shrink tension or orientation release stress (ORS) that film of the present invention needs are 500psi (2758kPa) or littler, preferably less than 400psi, are more preferably less than 300psi, most preferably less than about 250psi.Shrink tension is determined according to ASTM D-2838.ORS is a kind of tolerance to the suffered stress of film in the heat shrink process.What need is the ORS value that reduces the ROSO film.The ROSO film has at least an end to be bonded to container usually, is used around this container film.Label with high ORS value can be with enough stress application on the viscose glue seam around the container fixed labels in contraction process, thus infringement (damage) or damage (break) this seam.Reduce the possibility that ORS value has reduced jointing line (film-film) undermined or damage in contraction process.

Film of the present invention can use in any application, and this has benefited from it and triggers contraction in vertical or horizontal heat.Described film can be particularly useful as the ROSO label.For film of the present invention being changed into ROSO label of the present invention, film is cut into required width, and the one side of sided corona treatment film (with any order), print in the one side of film sided corona treatment then.Printing can be positioned on film " back of the body " face to produce the label of reverse printed.Locate against container at the back side of film, in the ROSO tag application, when film sees through the printing that film is observed the back side during around container.Usually adopt in the prior art available any method to add and carry out these steps man-hour at continuous coiled material.

Film of the present invention and label also advantageously have the perforation by film or label.When perforation needs most and is positioned at film next-door neighbour the part of narrow part or film are applied to ROSO around the part of container.Perforation allows gas to overflow, otherwise gas tends to be trapped between label and the container, makes label fit with container more tightly thus.Film of the present invention and label can comprise along the equally distributed perforation of film surface or comprise the regional perforation of special next-door neighbour's film (or label), and this zone is consistent around the narrowest part of container location with film (or label).Can at any time punch to the perforation of film of the present invention and label; But the printing of ROSO label need be punched to film and label after printing for convenience.

Following examples are used to illustrate the present invention, and are not used in definite four corner of the present invention.

Embodiment

Among the embodiment 1 and 2, use multilayer cast film production line to prepare two multilayer cast films.Each film has the A/B/C/B/A structure, and wherein the A layer is the top layer that comprises amorphous glassy polymer material, and the B layer is a binder course, and the C layer is a polyolefin layer.Film composed as follows:

Embodiment 1: the top layer, each accounts for about 25 weight % of film general construction, by Styron ^TM668GPPS (density=1.05g/cc, MFR=5.5 restrains/10 minutes (5kg/200 ℃)) makes.Binder course, each accounts for about 12 weight % of film general construction, is made by KRATON G1730M (density=0.90g/cc, MI=13 restrains/10 minutes (5kg/230 ℃)).Central core is the propylene plastic body of the class exploitation described in the WO 03/040442, and it contains the ethene of 5 weight %, and melt flow rate (MFR) is that (ASTM D1238,230 ℃, 2.16kg), density was 0.888g/cc to 8 grams in/10 minutes.Central core accounts for about 26% of general construction.The bulk density of film is about 0.974gm/cc.Average total film thickness before orientation step is about 112 microns.

Embodiment 2: the top layer, each accounts for about 21 weight % of film general construction, by Styron ^TM668GPPS makes.Binder course, about 12 weight % that each accounts for the film general construction are made by KRATONG1730M.Central core is the propylene plastic body of the class exploitation described in the WO 03/040442, and it contains the ethene of 5 weight %, and melt flow rate (MFR) is that (ASTM D1238,230 ℃, 2.16kg), density was 0.888g/cc to 8 grams in/10 minutes.Central core accounts for about 34% of general construction.The bulk density of film is about 0.961gm/cc.Average total film thickness before orientation step is about 124 microns.

The film extrusion condition of each embodiment is shown in Table I:

These cast films can adopt Bruckner Karo IV device to stretch under the condition shown in the Table II below.Film shown in stretching condition under stretch and do not have tearing or break.Film seems under the blend pattern and shows that they have the required fabulous rigidity of tag application by very (wrinkling) of stiff.The stretching condition and the shrinkage of shrink label films are as described below.Shrink and adopt ASTM D2732 (hot oil bath) to measure about 20 seconds of dip time.Shrink tension adopts ASTM D2838 to measure.

Table II

Embodiment	Draw direction	Draft temperature (℃)	Stretch rate	Preheating time (second)	Extensibility (%/minute)	Final thickness (mil)	Shrink tension (PSI) is under 135 ℃	Be contracted under 135 ℃
Embodiment	Draw direction	Draft temperature (℃)	Stretch rate	Preheating time (second)	Extensibility (%/minute)	Final thickness (mil)	Shrink tension (PSI) is under 135 ℃	Be contracted under 135 ℃	1	MD	130	4x	40	1000	1.05	150	75
2	MD	130	4X	40	1000	1.25	140	75	1	MD	130	4x	40	1000	1.05	150	75
2	MD	130	4X	40	1000	1.25	140	75	2	CD	130	4X	40	1000	1.2	55	75
1	CD	130	4X	40	200	1.0	70	75	2	CD	130	4X	40	1000	1.2	55	75
1	CD	130	4X	40	200	1.0	70	75	1	MD	130	5X	40	50	0.8	206	79
1	CD	130	5X	40	50	0.8	95	78	1	MD	130	5X	40	50	0.8	206	79
1	CD	130	5X	40	50	0.8	95	78	2	MD	130	5X	40	50	0.9	210	79
2	CD	130	5X	40	50	0.9	79	74	2	MD	130	5X	40	50	0.9	210	79

Above-mentioned data show uses film composite of the present invention can obtain the shrink label films that has fabulous contraction vertical or horizontal.As required, the shrink tension of film of the present invention also is low in all embodiments, less than 250psi.

Embodiment 3: prepared another five-layer structure.Provide the top layer by extruder A and C in this extrusion system, each top layer accounts for 15 weight % of film general construction.These layers are by doing mixed making with 70%STYRON 668 GPPS and 30%K-resin SB DKll (available from Chevron Phillips).Each binder course accounts for 10 weight % of film general construction, and D provides by extruder.Binder course is made by KRATON G1730M.Central core accounts for 50 weight % of film general construction, is provided by the extruder B in this system.Central core is the propylene plastic body of the class exploitation described in the WO 03/040442, and it contains the ethene of 5 weight %, and melt flow rate (MFR) is that (2.6kg), density was 0.888g/cc to 8 grams for ASTM D1238,230C in/10 minutes.

Adopt the speed change roll vertically being orientated, thereby give as multiple degree of orientation listed among sample 3-1 and the 3-2.

Processing conditions is listed in the Table III.

Table III

The contraction data of gained film as illustrated in fig. 1 and 2 among sample 3-1 and the 3-2.

The film performance of these samples is shown in the Table IV.

Table IV

		Sample 3-1	Sample 3-2
		Sample 3-1	Sample 3-2		The ASTM test method(s)
Average transparency	D1746	94.7	96.7		The ASTM test method(s)
Average transparency	D1746	94.7	96.7	Average Elmendorf tearability-type B (constant radius)-laterally	D1922	36.8	110.0
Average thickness type B-laterally (mil)		1.7	2.3		D1922	36.8	110.0
Average thickness type B-laterally (mil)		1.7	2.3
Average Elmendorf tearability-type B (constant radius)-vertically	D1922	14.0	14.0
	D1922	14.0	14.0	The average thickness type B-vertically		1.8	1.7
				The average thickness type B-vertically		1.8	1.7
				Average gloss 45 degree	D2457	108.8	102.0
Average mist degree	D1003	1.9	2.1	Average gloss 45 degree	D2457	108.8	102.0
Average mist degree	D1003	1.9	2.1
Tension force-laterally	D882
Tension force-laterally	D882			Average % elongation (%)		159.0	23.9
Limit in mean tension force (psi)		2931.8	2309.6	Average % elongation (%)		159.0	23.9
Limit in mean tension force (psi)		2931.8	2309.6	Average yield stress (psi)		2901.7	2309.6
				Average yield stress (psi)		2901.7	2309.6
				Tension force-vertically	D882
Average % elongation (%)		22.2	30.3	Tension force-vertically	D882
Average % elongation (%)		22.2	30.3	Limit in mean tension force (psi)		5842.2	5162.4
Average yield stress (psi)		4602.6	4407.9	Limit in mean tension force (psi)		5842.2	5162.4
Average yield stress (psi)		4602.6	4407.9	Shrink tension (psi)	105C	547	360
Shrink tension (psi)	135C	535	400	Shrink tension (psi)	105C	547	360

Embodiment

4 and 5 has prepared 5 layers of structure of another series.Provide the top layer by extruder A and C in this extrusion system, each top layer accounts for 15 weight % of film general construction.These layers are by doing mixed making with 70%STYRON 668 GPPS and 30%K-resin SB DKll (available from Chevron Phillips).Each binder course accounts for 10 weight % of film general construction, and D provides by extruder.Binder course is made by KRATON G1730M.Central core accounts for 50 weight % of film general construction, is provided by the extruder B in this system.Central core is the propylene plastic body of the class exploitation described in the WO 03/040442, and it contains the ethene of 5 weight %, and melt flow rate (MFR) is that (2.6kg), density was 0.888g/cc to 8 grams for ASTM D1238,230C in/10 minutes.

For embodiment 5, central core is the propylene plastic body of the class exploitation described in the WO 03/040442, and it contains the ethene of 9 weight %, and melt flow rate (MFR) is that (2.6kg), density was 0.876g/cc to 8 grams for ASTMD1238,230C in/10 minutes.

Film at first passes through the MDO roll, and has a mind to induce the orientation of a little, utilizes stenter laterally being orientated at film then.Also studied the transformation temperature of the orientation and the orientation of multiple degree.

The processing conditions of these materials is shown in the Table V:

Table V

Shrinkage is shown in Fig. 3 and 4.

Performance by these material gained films is shown in the Table VI:

Table VI

	The ASTM method	Sample 4-1	Sample 4-2	Sample 4-3	Sample 4-4	Sample 5
	The ASTM method	Sample 4-1	Sample 4-2	Sample 4-3	Sample 4-4	Sample 5
Average transparency	D1746	99.1	98.2	98.7	99.0	98.0
Average transparency	D1746	99.1	98.2	98.7	99.0	98.0
Average Elmendorf tearability type B (constant radius)-laterally	D1922	28.2	36.8	25.4	5.2	17.0
	D1922	28.2	36.8	25.4	5.2	17.0	The average thickness type B-laterally		1.6	1.4	1.2	1.2	1.3
							The average thickness type B-laterally		1.6	1.4	1.2	1.2	1.3
							Average Elmendorf tearability-type B (constant radius)-vertically	D1922	11.8	7.2	5.2	30.8	20.2
The average thickness type B-vertically		1.3	1.4	1.2	1.3	1.2		D1922	11.8	7.2	5.2	30.8	20.2
The average thickness type B-vertically		1.3	1.4	1.2	1.3	1.2
Average gloss 45 degree	D2457	107.8	95.8	108.7	91.9	105.6
Average gloss 45 degree	D2457	107.8	95.8	108.7	91.9	105.6
Average mist degree	D1003	1.3	3.1	1.4	4.3	1.3
Average mist degree	D1003	1.3	3.1	1.4	4.3	1.3
Tension force-laterally	D882
Tension force-laterally	D882						Average % elongation (%)		35.5	27.9	29.3	20.3	13.6
Limit in mean tension force (psi)		8065.6	12390.4	8151.3	13833.1	4716.2	Average % elongation (%)		35.5	27.9	29.3	20.3	13.6
Limit in mean tension force (psi)		8065.6	12390.4	8151.3	13833.1	4716.2	Average yield stress (psi)		5691.3	5084.1	5417.8	13833.1	4675.0
							Average yield stress (psi)		5691.3	5084.1	5417.8	13833.1	4675.0
							Tension force-vertically	D882
Average % elongation (%)		5.9	5.9	5.6	29.2	6.7	Tension force-vertically	D882
Average % elongation (%)		5.9	5.9	5.6	29.2	6.7	Limit in mean tension force (psi)		4621.1	4187.3	4293.9	4425.3	2820.7
Average yield stress (psi)		4621.0	4187.3	4293.9	4425.3	2820.7	Limit in mean tension force (psi)		4621.1	4187.3	4293.9	4425.3	2820.7
Average yield stress (psi)		4621.0	4187.3	4293.9	4425.3	2820.7
Shrink tension (psi)	105C	333	1212	567	1338	167
Shrink tension (psi)	105C	333	1212	567	1338	167	Shrink tension (psi)	135C	350	1098	473	1433	40

By

embodiment

4 and 5 as seen, the orientation temperature that changes in the tentering cabinet influences shrink tension (sample 4-2 and 4-4 carry out at a lower temperature).

In addition, center material is changed over than low density material and also can reduce shrink tension (sample 5).

Claims

1, a kind of multilayer oriented shrinkable film, it comprises that at least one top layer that comprises amorphous glassy polymer material and at least one comprise the central core of polyolefin layer.

2, plural layers according to claim 1, wherein, described amorphous glass polymers is a polystyrene material.

3, plural layers according to claim 1, wherein, the gross density of described film is less than 1.0g/cm ³

4, plural layers according to claim 3, wherein, the gross density of described film is less than 0.98g/cm ³

5, plural layers according to claim 1, wherein, described film is in vertical or horizontal preferred orientation.

6, plural layers according to claim 5 wherein, are rightabout twices in the orientation of a direction at least.

7, plural layers according to claim 5 wherein, are rightabout three times in the orientation of a direction at least.

8, plural layers according to claim 1, wherein, the shrink tension of described film is less than 500psi.

9, plural layers according to claim 1, wherein, the shrink tension of described film is less than 250psi.

10, plural layers according to claim 1, it also is included in the binder course between at least one top layer and at least one central core.

11, plural layers according to claim 2, wherein, described polystyrene material comprises one or more in GPPS, HIPS, SBS, SIS, SEBS or the K-resin.

12, plural layers according to claim 11, wherein, described polystyrene material comprises that average rubber particle size is less than about 1 micron HIPS.

13, plural layers according to claim 1, wherein, described amorphous glassy polymer material comprises one or more among PETG, amorphous PET, amorphous state PLA or the PVC.

14, plural layers according to claim 1, wherein, described polyolefine material comprises one or more low density polyethylene (LDPE)s, LLDPE, very low (or ultralow) density polyethylene, polyethylene plastomers and elastomer, for example evenly linear tetrafluoroethylene polymer and substantially linear ethene polymers, intermediate density polyethylene and the high density polyethylene (HDPE) of branching), homopolymer polypropylene (" hPP ") random copolymer polypropylene (" RCP ") or acrylic plastic body and elastomer.

15, plural layers according to claim 14, wherein, described polyolefine material is plastic body or elastomer.

16, plural layers according to claim 15, wherein, described polyolefine material is acrylic plastic body or elastomer.

17, plural layers according to claim 10, wherein, described binder course comprises one or more in SEBS, SEPS, EVA, SBS, SIS or the K-resin.

18, plural layers according to claim 10, wherein, described amorphous glassy polymer skin layer accounts for 10 weight % to 80 weight % of whole film, and the polyolefin internal layer accounts for 20 weight % to 90 weight % of whole film, and binder course accounts for 0 to 15 weight % of whole film.

19, a kind of shrink label that comprises each described plural layers of aforesaid right requirement.

20, shrink label according to claim 19, wherein, described shrink label is with (ROSO) label that contracts with volume.

21, shrink label according to claim 19, wherein, described shrink label is a sleeve label.

22, shrink label according to claim 20 is characterized in that described label shrinks greater than 40% in the direction of preferred orientation under 135 ℃.

23, shrink label according to claim 21 is characterized in that described label shrinks greater than 40% in the direction of preferred orientation under 135 ℃.